Contaminants in Seaweed: Food Safety Report

Is Scottish seaweed safe to eat?

Scottish seaweed is broadly safe to eat. Testing of 95 samples from across Scotland, alongside a review of over 3,000 results from European seaweed studies, found that levels of most toxic elements (including cadmium, lead and mercury) fall within recommended safety limits. The main considerations are naturally occurring iodine and, in specific species, inorganic arsenic.

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How much iodine is in seaweed?

Levels vary widely between species, and brown kelps such as Laminaria and Saccharina latissima (sugar kelp) can exceed recommended daily intake even in small portions. Iodine in Scottish seaweed is comparable to seaweed across Europe, and levels can be reduced through processing.

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Which seaweeds are high in arsenic?

Inorganic arsenic (the most toxic form) is a species-specific risk in seaweed. Laminaria digitata (oarweed) consistently shows high levels and should be treated as a high-risk species. Most other Scottish species, however, fall within proposed limits. 

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Do heavy metals in seaweed pose a health risk?

Heavy metals in Scottish seaweed are generally low. No samples exceeded the recommended limits for mercury or cadmium. Levels were consistent with seaweed tested across Europe, indicating low risk at normal consumption levels.

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What does this mean for seaweed producers?

For producers, the report reinforces the value of baseline and ongoing contaminant testing, species-specific risk assessment within a HACCP plan, and good handling and hygiene practices for food safety assurance amongst customers and regulators.